OBJECTIVETo explore the effects of di(2-ethylhexyl)phthalate (DEHP) on neonatal mice's testes and Leydig cells in vivo.

METHODSPregnant mice were exposed to DEHP at the dose of 100 mg/kg, 200 mg/kg or 500 mg/kg (body weight) per day by gavage from gestation day 12 (GD 12) through postnatal day 3 (PND 3), respectively. The testis and body weights, testicular histopathology and the activity of 3beta-hydroxysteroid dehydrogenase (3beta-HSD) of the neonatal mice were investigated.

RESULTSThe body and testis weights of the male mice's offspring were significantly reduced following DEHP exposure. Leydig cell morphology was affected significantly by DEHP as compared with the controls. Leydig cells obviously increased in the neonatal mice's testes on PND 15 and PND 30 when exposed to DEHP (500 mg/[kg x d]). Activities and positive area of the steroidogenic enzymes 3beta-HSD immunoexpression decreased markedly when exposed to DEHP (100 mg/[kg x d] or 200 mg/[kg x d]). Image analysis showed a decrease in the activities of 3beta-HSD in the animals exposed to DEHP (500 mg/[kg x d]), but an increase in the positive area of 3beta-HSD immunoexpression as compared with the control animals on PND 15 (P < 0.01).

CONCLUSIONDEHP affects the Leydig cell morphology, the activity of 3beta-HSD, the testis and body weights and the testicular histopathology of neonatal mice, and it may function as an antiandrogenic agent.